Cognomen Fermencio (Fermencio 
) , worldwide, is an extremely rare surname. The cognomen Fermencio is habitual in Latin America and the Caribbean, particularly Mexico, where it is an extremely rare surname. More prevalently, Fermencio is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Fermencio | Mexico, Brazil, United States, Philippines |